Exsolving Nanoparticles in LaCrO3-Based Materials for CO2 Electroreduction in Solid Oxide Electrolysis Cells (SOECs)

The electrochemical conversion of CO₂ into fuels and valuable chemicals is a promising strategy for reducing greenhouse gas emissions while enabling renewable energy storage. In this context, Solid Oxide Electrolysis Cells (SOECs) offer high efficiency and current density, making them attractive for industrial CO₂ utilization. This thesis focuses on the development of cathode materials for CO2 electroreduction. The materials are chromate-based single perovskites doped in B-site with Fe, in A-site with Sr, and with exsolved nanoparticles of transition metals such as Ni, Co or Cu. The designed compositions are La0.8Sr0.1Cr0.5Fe0.4X0.1O3 with X = Ni, Co, or Cu. Cr- based perovskites have emerged as structurally stable at the reaction conditions. Sr doping confers a good ionic conductivity thanks to the induced high oxygen vacancy concentration due to the size difference with La. Fe doping enhances electric conductivity thanks to its +3/+2 redox couple. The exsolved metal nanoparticles increase the active surface and thus the catalytic performance The materials were synthesized via the citrate combustion route and characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy, H₂-temperature programmed reduction, and CO₂-temperature programmed desorption. Their electrochemical performance was evaluated in symmetric and full-cell configurations using electrochemical impedance spectroscopy under H₂- and CO₂-containing atmospheres and using chronoamperometry. The results provide insights into the effect of exsolved Ni, Co, and Cu nanoparticles on electrode properties and contribute to the development of efficient, stable, and coke-resistant cathodes for CO₂ electrolysis.